Both dimostra and motiva are in the present indicative, third person singular.
That is because the subject is questo fatto, which is singular.
The infinitives are:
Because the same subject, questo fatto, applies to both verbs.
So:
means:
Italian, like English, does not need to repeat the subject when the same subject continues with another verb joined by e.
You could repeat it for emphasis, but normally you would not:
This is grammatical, but sounds unnecessarily repetitive.
Because la differenza is the direct object and refers to the difference as a definite idea.
Italian often uses the definite article where English also uses it, and sometimes even where English might leave it out.
Here:
It sounds natural with the article because the sentence is talking about a specific difference, even if it is understood from context rather than stated explicitly.
In Italian, possessive adjectives usually go together with the definite article.
So:
This is different from English, which usually does not use an article before possessives.
A common exception is with some singular family members:
But that exception does not apply here, so la nostra posizione is correct.
Not necessarily in the emotional sense of English motivates.
In a sentence like this, motivare often means:
So motiva la nostra posizione can mean something like:
A very literal translation, motivates our position, is possible, but in English it may sound slightly less natural depending on context.
Yes, Italian word order is fairly flexible, although the original sentence is the most neutral and natural.
Original:
You could change the order for emphasis, for example:
This is still grammatical, but it slightly changes what feels more prominent.
You could also front an object in special contexts, but that would usually add emphasis or sound more literary.
So the given order is the straightforward, standard one.
Because e is the normal form of and in Italian.
The form ed may be used before a word beginning with e to avoid awkward repetition of the sound, for example:
But in modern Italian, even that is often optional and less common than learners sometimes expect.
Here the next word is motiva, which begins with m, so plain e is correct:
Yes. Both verbs are being used transitively, meaning they take direct objects.
There is no preposition before those nouns because they are direct objects.
Those would be wrong in this sentence.